the whitish tissue looks like sun burn to me ... how much sun is your plant in?

or herbicide damage.. has anything been sprayed in the area in the last month?

what is the ambient humidity?

isreal isnt MI, USA .. lol .. mine grow well in shade... high humidity ... very little direct sunlight ....

good luck .. ken

Ken- This plant is not mine so I will find out about the possibility of herbicidal damage. The plant is situated on a roofed porch with bright shade and no direct sunlight. It did beautifully all summer despite the 37-40 degree weather here and these lighter patches, turning to either like a webbed spot or brown/grey/blackish tips which dry up. There are signs of this on most of the foliage in varying degrees and although it is unattractive the plant does not seem to be suffering. The guy at a local greenhouse suggested it is some kind of fungus which is new in this area affecting hortenzias - does this ring a bell? Also, I do not know what ambient humidity is. I can tell you that as a rule it is extremely hot and dry here until winter. Although the coastal areas in Israel are very humid, our climate in northern Israel is similar to that of southern California. What sort of humidity is good for hyrangeas? Do they liked to be sprayed/pebble trays etc? I know this isn't the correct forum but I received one as a gift and hope that this time (unlike all the others!) I will succeed. I think I have found it the perfect spot and so far so good.
Any advice you may have re the leaf problem will be very much appreciated.
Dory

hey ... i hit the limit of my knowledge ....

below is a link to a fast referral on culture ....

also, paste this in to you browser:

http://www.google.com/search?hl=en&rls=RNWE,RNWE:2005-14,RNWE:en&sa=X&oi=spell&resnum=0amp;ct=result&cd=1&q=hydrangeas&spell=1

i think the first thing you have to do .. is get a proper name . since there appear to be a multitude of 'types' .... and then you have to define if there are cultural specificities to that type .... and then go from there ...

mine die back almost to the ground in winter .. maybe yours is just tired.. and needs some down time .... in other words.. it might be reacting to day length issues and going into some type of 'ugly' semi-dormancy ....

what you really need is a referral to a southern gardener ... where is rhizo when you need her.. i will email her and ask her to chime in ...

good luck ... ken

Here is a link that might be useful: read down to STRESS / FUNGUS / INSECTS

I saw this and didn't respond because there were just too many unknown variables. Let's muddle through some of them!

First of all, it is NEVER EVER EVER the right policy to mist plants that are showing any sign of a disease infection. With few exceptions, that's one way that fungal spores are spread.

There are many problems associated with container grown plants, much more so than those planted out in the real world. Soils that are too slow to drain, plants that get watered too often, too infrequently, or just plain incorrectly, excess fertilization, container size to root ball ratio, and so on all contribute to problems. I think that you know, Dory, how important a good potting medium is.

Know, too, that hydrangeas (especially greenhouse, florist, container grown) are susceptible to several important fungal and viral diseases. These lesions look more like anthracnose than some of the other possibilities, but without seeing more of the plant (including reverse leaf surfaces), that would be a guess. Powdery mildew could be a possibility; or it could be a combination of things. However, from what I see, it does look fungal.

That means that there's hope. It would be my guess that this plant would thrive if planted in situ, in a shady location. There's nothing like a thriving root system to fight off plant diseases. However, I'd sure give your friend some container plant counseling (in relation to the points mentioned earlier), have all infected leaves removed immediately, and perhaps look into an all purpose fungicide regime.

Commercially grown hydrangeas are treated frequently with fungicides. Once they leave the protection of the grower, it is common for them to show signs of the diseases that chemicals have kept at bay, especially if they are not happy with their growing conditions.

If the relative humidity is very low, then a pebble tray might not be a bad idea. The roots must not sit IN water, however.

OK....no more shooting darts with my eyes closed! I hope your friend's plant recovers!

I'll just ask....is this an overall problem....many leaves showing this damage.....or is it just one.
If it is of minor nature to so few leaves, put it down to a passing bug....remove the leaf and go about your life.
If it is an overall problem, suspect a bug or maybe a spore damage and give it a general insecticide like insecticidal soap or a fungicide. See what comes later.

In Isreal, can you buy a product called "Benomyl"...its a lime sulfur fungicide. Or how about the product "Bordeaux Mixture"...a copper and lime sulfate fungicide.